of choice !
Kit
VK2LL
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Lux, James P
Sent: Sunday, 5 July 2009 8:12 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Broken Ovenaire OSC 85-50
Hi Joe
I am just a radio amateur and I build a lot of oscillators for my need,
including a GPSDO tunable with CW25-TIM GPS receiver chip set. Please
allow me to share my usual trouble shooting when oscillator is not working
properly.
I see an oscillator is just only a high gain amplifier with
Pascal Nguyen wrote:
Hi Joe
I am just a radio amateur and I build a lot of oscillators for my need,
including a GPSDO tunable with CW25-TIM GPS receiver chip set. Please
allow me to share my usual trouble shooting when oscillator is not working
properly.
I see an oscillator is just only a
Hi Joe
Please open the link below
http://www.airlab.com.au/nuts/joe_1.htm
for an update of a simulated fault from an out of tune of the narrow band
pass filter
Kind regards
Pascal Nguyen
___
time-nuts mailing list -- time-nuts@febo.com
To
Pascal
There is also a parallel resonance in the L2 C6 C7 network.
Plus several self resonances in L2.
To get a more complete picture you need to also include the phase shift
and gain over a wide band as the phase shift determines whether
oscillation is possible when the loop gain is greater than
Pascal Nguyen wrote:
Hi Joe
Please open the link below
http://www.airlab.com.au/nuts/joe_1.htm
for an update of a simulated fault from an out of tune of the narrow band
pass filter
Kind regards
Pascal Nguyen
___
time-nuts mailing list --
Subject: Re: [time-nuts] Broken Ovenaire OSC 85-50
Pascal Nguyen wrote:
Hi Joe
Please open the link below
http://www.airlab.com.au/nuts/joe_1.htm
for an update of a simulated fault from an out of tune of the narrow
band pass filter
Kind regards
Pascal Nguyen
-nuts] Broken Ovenaire OSC 85-50
WarrenS wrote:
A couple more thoughts;
Is the VCC (Red wire) current draw correct?.
Should be 1.3 ma (per the schematic values) with the 470 Ohm and
more like 7 plus ma with the 47 ohm.
AND I don't remember seeing, IS the Freq real close AND can
**
- Original Message -
From: Bruce Griffiths bruce.griffi...@xtra.co.nz
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Friday, July 03, 2009 11:08 PM
Subject: Re: [time-nuts] Broken Ovenaire OSC 85-50
Warren
My Spice model of the dc
11:08 PM
Subject: Re: [time-nuts] Broken Ovenaire OSC 85-50
Warren
My Spice model of the dc levels in the oscillator indicate a current
more like 4mA in the 510 ohm resistor.
Bruce
WarrenS wrote:
I just saw your schematic of the rest of the buffer circuit. Sorry I missed
: [time-nuts] Broken Ovenaire OSC 85-50
Warren
The Vcc dc current doesn't change much if the circuit is oscillating (at
least it shouldn't if the circuit operating correctly - the active
devices aren't supposed to saturate as thats adds too much phase noise).
My simulations were over
G'day Joe,
My call on this question is: very seldom with a properly designed
circuit and crystal (NO flames please on these descriptions !)
Having said that, I have a couple of broken crystals from once-working
HP E1938A oscillators. All appear to have some form of physical
fracture or
Kit
If you are confident of your diagnosis then you have little to lose.
The crystal is defunct and isn't going to fix itself so it may be
instructive to take a peak inside.
However don't the E1938 cans have an internal vacuum?
Some care in opening may be required.
Bruce
Kit Scally wrote:
Of Bruce Griffiths
Sent: Saturday, 4 July 2009 6:38 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Broken Ovenaire OSC 85-50 - crystal failure ?
Kit
If you are confident of your diagnosis then you have little to lose. The
crystal is defunct and isn't going to fix
of precise time and frequency measurement time-nuts@febo.com
Sent: Saturday, July 04, 2009 12:24 AM
Subject: Re: [time-nuts] Broken Ovenaire OSC 85-50
I get a 'if working correct' Vcc of about 3.5V
If the Vcc is 2.49 volts, I calculate a 3ma unaccounted for current draw from
something.
So I have
notes.
Joe
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of WB6BNQ
Sent: Friday, July 03, 2009 9:20 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Broken Ovenaire OSC 85-50
I agree with Warren
time and frequency measurement
Subject: Re: [time-nuts] Broken Ovenaire OSC 85-50
Here is a new observation about low Vcc.
It is not likely that the Osc Vcc voltage and the Varicap freq control
voltage is coming from the same 510 Ohm resistor without a regulator.
Something is missing
I've not attempted to butcher a capsule open to determine the cause -
this to my mind is bordering on the sacrilegious but if given
absolution from another TimeNut, I may attempt it and photograph the
results ...
What have you got to lose? Is it good for anything else?
I probably wouldn't
On 7/4/09 1:49 PM, Hal Murray hmur...@megapathdsl.net wrote:
I've not attempted to butcher a capsule open to determine the cause -
this to my mind is bordering on the sacrilegious but if given
absolution from another TimeNut, I may attempt it and photograph the
results ...
What have
: [time-nuts] Broken Ovenaire OSC 85-50
Joe [Trantham]
Whilst its easy enough to construct a miniature RF current probe using a
small ferrite core which is slipped over the wire in which the current is to
be measured, constructing one using a split ferrite toroid is more difficult
as such toroids
(This is a repost to see if I can figure out why the original was
scrubbed. Sorry for the duplicate.)
An update on the Broken Ovenaire OSC 85-50.
I prepared a 'schematic' of the Output Board and the Oscillator
Board (attached) and I have lots of pictures of the external
Mike Monett wrote:
(This is a repost to see if I can figure out why the original was
scrubbed. Sorry for the duplicate.)
An update on the Broken Ovenaire OSC 85-50.
I prepared a 'schematic' of the Output Board and the Oscillator
Board (attached) and I have lots of
Mike Monett wrote:
(This is a repost to see if I can figure out why the original was
scrubbed. Sorry for the duplicate.)
An update on the Broken Ovenaire OSC 85-50.
I prepared a 'schematic' of the Output Board and the Oscillator
Board (attached) and I have lots of
the gain,
It would seem better to bypass the 470 ohm resistor with a cap in series with
the 47 ohms.
ws
- Original Message -
From: Mike Monett xde-l...@myamail.com
To: time-nuts@febo.com
Sent: Friday, July 03, 2009 11:50 AM
Subject: Re: [time-nuts] Broken Ovenaire OSC 85-50
Mike Monett wrote:
A couple of things. First, trying to measure the currents in the
circuit with a ferrite toroid won't do you much good. You don't
know what the currents should be, and the secondary of the toroid
transformer requires a termination resistor. The value
: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of WarrenS
Sent: Friday, July 03, 2009 7:49 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Broken Ovenaire OSC 85-50
Here is my two cents worth
20 mv output, sure sounds like something
Mike Monett wrote:
Mike Monett wrote:
A couple of things. First, trying to measure the currents in the
circuit with a ferrite toroid won't do you much good. You don't
know what the currents should be, and the secondary of the toroid
transformer requires a termination
I agree with Warren. The VCC seems way too low. Interestingly, noone else
seems to think so,
or did not notice it.
BillWB6BNQ
WarrenS wrote:
Here is my two cents worth
20 mv output, sure sounds like something is broken.
It should be fixed before it is modified.
The 2.49 volts on
Broken Ovenaire OSC 85-50
J. L. Trantham jltran at worldnet.att.net
Sat Jul 4 02:07:48 UTC 2009
I did not realize that this post would generate this much
discussion.
While I have a BEE and MSEE, I am a practicing Cardiac
Electrophysiologist and it has
Message -
From: Mike Monett xde-l...@myamail.com
To: time-nuts@febo.com
Sent: Friday, July 03, 2009 11:50 AM
Subject: Re: [time-nuts] Broken Ovenaire OSC 85-50
An update on the Broken Ovenaire OSC 85-50.
I prepared a 'schematic' of the Output Board and the Oscillator
Board
WB6BNQ wrote:
I agree with Warren. The VCC seems way too low. Interestingly, noone else
seems to think so,
or did not notice it.
BillWB6BNQ
It was noticed, but it is consistent with the resistor values used in
the circuit.
The crystal current is determined by the dc emitter
Of WarrenS
Sent: Friday, July 03, 2009 7:49 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Broken Ovenaire OSC 85-50
Here is my two cents worth
20 mv output, sure sounds like something is broken.
It should be fixed before it is modified.
The 2.49 volts
.
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of WarrenS
Sent: Friday, July 03, 2009 7:49 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Broken Ovenaire OSC 85-50
Here is my two cents worth
20 mv output
*
- Original Message -
From: Bruce Griffiths bruce.griffi...@xtra.co.nz
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Friday, July 03, 2009 8:21 PM
Subject: Re: [time-nuts] Broken Ovenaire OSC 85-50
WarrenS wrote:
Here is my two cents
*
- Original Message -
From: Bruce Griffiths bruce.griffi...@xtra.co.nz
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Sent: Friday, July 03, 2009 8:21 PM
Subject: Re: [time-nuts] Broken Ovenaire OSC 85-50
WarrenS wrote:
Here is my two cents worth
20
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Friday, July 03, 2009 8:36 PM
Subject: Re: [time-nuts] Broken Ovenaire OSC 85-50
WB6BNQ wrote:
I agree with Warren. The VCC seems way too low. Interestingly, noone else
seems to think so,
or did not notice it.
Bill
] Broken Ovenaire OSC 85-50
WB6BNQ wrote:
I agree with Warren. The VCC seems way too low. Interestingly, noone else
seems to think so,
or did not notice it.
BillWB6BNQ
It was noticed, but it is consistent with the resistor values used in
the circuit
...@xtra.co.nz
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Friday, July 03, 2009 9:55 PM
Subject: Re: [time-nuts] Broken Ovenaire OSC 85-50
WarrenS wrote:
A couple more thoughts;
Is the VCC (Red wire) current draw correct?.
Should be 1.3 ma (per the schematic values
into those small spaces?
Joe
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Bruce Griffiths
Sent: Thursday, May 28, 2009 12:13 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Broken Ovenaire OSC 85-50
of precise time and frequency measurement
Subject: Re: [time-nuts] Broken Ovenaire OSC 85-50
Joe
Low output can be caused by a high impedance path, an open circuit
component, an open solder joint, a low value cap, low gain transistor,
etc.
The oscillator limits by either saturating
PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Broken Ovenaire OSC 85-50
Joe
Whilst its easy enough to construct a miniature RF current probe using a
small ferrite core which is slipped over the wire in which the current
is to be measured, constructing one
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Bruce Griffiths
Sent: Thursday, May 28, 2009 7:13 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Broken Ovenaire OSC 85-50
Joe
Whilst its easy enough
Of Bruce Griffiths
Sent: Tuesday, May 26, 2009 10:43 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Broken Ovenaire OSC 85-50
Joe
A quick analysis if the buffer indicates that the gain with a 50 ohm
load is about 1x.
The gain into a 1M load should be about 4x
Griffiths
Sent: Wednesday, May 27, 2009 11:03 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Broken Ovenaire OSC 85-50
Joe
Low output can be caused by a high impedance path, an open circuit
component, an open solder joint, a low value cap, low gain transistor
[mailto:time-nuts-boun...@febo.com] On
Behalf Of Bruce Griffiths
Sent: Tuesday, May 26, 2009 10:43 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Broken Ovenaire OSC 85-50
Joe
A quick analysis if the buffer indicates that the gain with a 50 ohm
load
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Gordon Batey
Sent: Sunday, May 24, 2009 6:50 PM
To: time-nuts@febo.com
Subject: Re: [time-nuts] Broken Ovenaire OSC 85-50
I had an earlier model 20 mhx ovenaire osc that had very low output
I have an Ovenaire OSC 85-50 10 MHz OCXO that is a frequency reference for a
HP 5316B frequency counter. It oscillates but the output amplitude is about
20 mV.
I would like to try to repair it. It looks like it is sealed with epoxy.
Any suggestions on how to open it other than scraping the
Hello Joe,
At one time I used methylene chloride, a clear liquid, to dissolve epoxy.
Took awhile, but the epoxy did soften up and I could easily chip it out.
I soaked the item in a large covered pickle jar for a couple of days.
The liquid and vapors of the solvent got to the epoxy nicely.
I would avoid the methylene chloride. It is very prone to capillary
wicking/pumping and will definitely damage plastic cased components if gets to
them. It has been used to de-pot semiconductors.
It can pump a whole lot of itself through tiny cracks in a short period of time
particularly
I had an earlier model 20 mhx ovenaire osc that had very low output. I
opened it up with a scalpel and found the TTL chip had failed and was only
letting a small amount of the osc signal thru. I was able to use an
external TTl (74LS20 I think) to restore it. As I recall I was unable to
readily
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